Reviewing External Resources and Legacy Systems

In an ideal world, your entire application might only contain Java components and applications, but it is not an ideal world. Very few architects have the opportunity to design entire Java systems from the ground-up, and very few enterprise developers have the opportunity to solely work on these types of systems. In reality, systems are heterogeneous in nature; that is, they are made up of many different parts. Figure 19.1 shows a complex heterogeneous environment that shows an array of clients attempting to access the services provided by a vast array of non-Java applications and systems.

Figure 19.1. A complex heterogeneous environment.

As you can see, the system consists of Enterprise Information ...

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